Pope Benedict XVI prayed with tearful victims of clergy sex abuse in an extraordinary gesture during his first papal trip to America.

The pontiff has made atoning for the great shame of the US church the cornerstone of his visit.

Benedict's third day in the US began with a packed open-air Mass, celebrated in 10 languages at a baseball stadium, and included a speech to Roman Catholic college and university presidents.

But the real drama happened privately, in the chapel of the papal embassy between events.

The Rev Federico Lombardi, a papal spokesman, said the Pope and Boston Cardinal Sean O'Malley met a group of five or six clergy sex abuse victims for about 25 minutes, offering them encouragement and hope. The group from O'Malley's archdiocese were all adults, men and women, who had been molested when they were minors. Each spoke privately with the Pope.

"They prayed together. Also, each of them had their own individual time with the Holy Father," Mr Lombardi said. "Some were in tears."

Bernie McDaid, one of the victims, said in an interview with CNN that he told the Pope he was an altar boy when he was abused. "I told him that he has a cancer growing in his ministry, and needs to do something about it," he said.

Over 4,000 priests have been accused of molesting minors in the US since 1950. The church has paid out more than £1 billion.